The web has become a popular target platform for applications. The differences in user experience between browser based applications and desktop applications have become smaller due to the enriched user experience enabled by the Ajax technique. Nevertheless, developing Ajax based internet applications is a complex task and requires the developer to intertwine many standards and languages. This thesis presents the WebDSLx extension for the WebDSL compiler. The compiler and
extension allows the developer to create rich internet applications in an intuitive way, since many details are taken care of by the abstractions provided in the model. WebDSLx allows to define a rich interaction pattern between user and application, based on the concepts of delta updates and reusable widgets. The abstractions provided are based on an analysis of proven successful abstractions in the development process of desktop applications. As a result, the WebDSLx extension provides a simple model based approach to a formerly tedious task.